On Tuesday, the Food and Drug Administration approved investigating treatment options for the outbreak by using plasma collected from recovered COVID-19 patients. Doctors in China have already tried these specific COVID-19 treatments using what the history books call “convalescent serum,” also known as donated plasma.

However, there’s no guarantee it will work. Dr. Arturo Casadevall of Johns Hopkins University’s school of public health told The Associated Press: “We won’t know until we do it, but the historical evidence is encouraging.”

The FDA is still continuing to work with its government partners including the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) to develop master protocols in order to coordinate the collection and use of COVID-19 plasma.